Why are habits so hard to break?

According to a recent study conducted by researchers at Duke University, bad habits have the ability to leave lasting marks on specific circuits in the brain. This causes us to constantly seek a ‘fix’ in the form of feeding our cravings.

“One day, we may be able to target these circuits in people to help promote habits that we want and kick out those that we don’t want,” said the study’s senior investigator Nicole Calakos, M.D., Ph.D., an associate professor of neurology and neurobiology at the Duke University Medical Center.

The experiment saw groups of otherwise healthy mice react to being exposed to varying levels of sugar. The process entailed pressing a lever to receive the sweets. The mice who became hooked on the sugar kept pressing the lever long after the sweets were taken away.

This group of mice were then compared to mice who had not developed a sugar addiction. In particular, the researchers looked into electrical activity in the basal ganglia, an area that controls motor actions and compulsive behaviors, including drug addiction.

Scientists found that the pathways that signal the ‘stop’ and ‘go’ responses in the basal ganglia, were more active in the sugar-addicted mice.

Similarly, when the groups were assessed separately, the mice who had developed a habit showed no sign of registering a ‘stop’ message before the ‘go’ message took over. This was directly paralleled by the non-addicted mice, who registered a ‘stop’ signal before ‘go’.

“The go pathway’s head start makes sense,” said Calakos. “It could prime the animal to be more likely to engage in the behavior.”

“Calakos also said some researchers are beginning to explore the possibility of treating drug addiction using transcranial magnetic stimulation or TMS, a noninvasive technique that uses magnetic pulses to stimulate the brain.” according to a press release on the Duke University website.

“TMS is an inroad to access these circuits in more severe diseases,” says Calakos, in particular targeting the cortex, a brain area that serves as the main input to the basal ganglia.”

Calakos says she and her team are working on theories that can be applied to more ordinary habits and how they manifest themselves in our subconscious.

The research will hopefully shed light on the difference between ordinary habits and more problematic ones that can cause severe damage like addiction and obsessive-compulsive disorders.